Method and apparatus for making flexible tubular coverings



p 1952 E. A. FARRELL 2,609,312

METHOD AND APPARATUS FOR MAKING FLEXIBLE TUBULAR COVERINGS Filed June 28, 1947 2 SHEETS-SHEET l INVENTOR fan A e0 ,4. AZFEAL w- WM;

ATTORNEY E. A. FARRELL Sept. 2, 1952 2 SHEETSSHEET 2 Filed June 28, 1947 Z Mu.

ATTORNEY llllllllllllllllllllllllllllll 1 INVENTOR $5M w iwkh OWWMMMOOOKV [Ill-H inn/A20 A. flees. A/

Patented Sept. 2, 1952 s'UNITED STATES -METHOD AND'APPARATUS FOR MAKING FLEXIBLE TUBULARQCOVERINGS EdwariA. Farrell, North 'Plainfield; N.'J., as-

signor "to. Johns=Manville Corporation, New Y ork,' N. Y a" corporation or New' *York Application June. 28,

8''Claims. :1 The present invention relates-to; flexible, tu- 01311131: coverings.particularly; adapted foruse as dnsulatingreoverings for-pip.es, tubesand the like. i; The invention also; relates. to a .method and ap- Qparatus, :for .-themanufacture of such coverings. .The prineipal. object of: the invention is the gproyision-rof ianflmproved flexible covering .and ism'ethod and apparatus for making.- the same, the ncovering'icomprising aseamless sleeve surround- .r tingrand. eontaining..-.a. bonded tubular insulating iiibOflY. v I

aAnnther. object of the .invention is1.the :provissionnof;;a-;tubular:covering..-comprising an. outer, .peamless .sleeve;.:fabricated preferably of knitted metal strandszandaa tubular? insulatingbody of i fibrousaxmaterialasuchc as: asbestos, @mineral wool, fiber: or other: fibrous. material within. the nsleeveiithe bodywcontaining. asdistributedahardzenedhinder.

.iAnother. object of; {the invention -is- :the provizsionrof am'ethod: and: apparatus for fabricating aagproductofithettypedescribed above, the steps 1 1 f -the":method:. being; carried :out." in .1 sequence whereby: :the. covering. .v-iis c r-completed. in a; single :-.series..- of-; operations and: continuous production axisobtained. H further object:of.-.the;invention istheproyiion ofwamethods and; apparatus :for: knitting: or therwise: :fabricating: a tubulansleeve around a ';1=-forming@member,introducingafibrus insulating .afilling .containingea. distributedbinder =into...the esleeves as rit -.-is :drawn off. =the.. formingmember,

setting or: 1curingithe binder. .-..In .theoperan-tion; the l-insu-lating-imaterial.-is. confined between sztrhen forming .tmember and-.a. centrally located -.mandrel-whereby. it:is shaped to tubular form.

Azstillfurther. "object; of. the inventionis .the n -provision :of a method: and apparatus as I deaseribed abovednwhich ,the mandrel-is of. a. char- ...acter.-to impart heatitohthe hQdY-rOffibGI'S. .The applicatiomofvheatnsets the binderein the,v event Ma mthermo=settingh binderfiismused, ormserves to nsoftenlthelbinder. -where.'.-=the binder is (at thermopla'sti c,. 'the'.body..thereafter .beingcooled. The ,imandrelmays serve as a heat-imparting medium insever'al ways ;l. for 1examp1e, .it maybe. electri- ..c'ally.;heated to provide a relatively localized heating efiect. adjacent the .inner circumference i lofnthe; tubular. body ..or .it..may. .serve as means iflforbireulatinglhot ,air, steam .or the like through 'ifthei-tubularbody; .Additionalheating.meansmay fa-bet usdltos applyL1l1eat..-to-. the. exterior .of the .xcoveringasliitis formedl Myinve'rition willbeimore fullylunderstoodand .lfimither.objects.an'd.advantages will becomaap- 194 7,-.-Serial-No. 7575820 (C1."154+27) I 1.2 j

parent when. references is .madeito the .morej.detailed description. of a preferred.embodimentabf the invention --.which=is to follownndztdthaac- .eompanying drawings inwhich: Fig. 1 is a perspective viewofiartubular,cover- ..ing-in-accordance. with theinstant invention;-,.

. liighz is a.-diagrammatic, perspective..viewspf (an/ apparatus embodying... the. ..invention.. Yand',}for .carrying.outtheomethoduthereof;

Fig. 3 is a sectional view, taken on thegline 3-3 of Fi .2;

FigiAisa .viewasimilar, toZEjigr .3 illustrating a .modification of.the.inyention;..and

Eiga 5 is a view similarflto Fig.3 illustrating-la further.modification. Referring now \to;..the. drawings and-,particu- .laLrlyto. Fig. 1,.the productof the invention-com- ,prises a tubular. covering l0 :-adapted,particula1;ly 1 foreuse as insulation for pipes, tubes. and -similar equipment. I-Iowever,.iaswill. -be-;appreciated,sthe product may .have uses-other than .forinsulating ,purposes; and maybe employed: .to .-cov er...- other elements thani-thoseystated. The.;covering ineludes an. outer. sleeve .1 2; surrounding;- ancbconxtaininga fibrous,=tubular body lfi. l

-. Sleeve I2 isoia.stretchable,.distortablei character and .is: suitably fabricatedtby knittingfiex- :ible strands on a character to -impart ;to the prod- -.aict any :desired properties .--.or--: characteristics.

7 Preferably for this .ipurposeemetallic;strands; are

employed. If. resistancetto -.high temperatures is a factor, metals such as.-.chrome.zall oys,;nickel :.-steel '1 alloys, ..-nickel copper alloys sand -.-;.nickel chrome alloys. of. conventionaltypesmaybeused.

35.;If ;heat.-resistance-is not. a factor,-. softermetals,

..-. asbestos or even organic. materialsrmayr:beem- ..-ployed. I Where meta1-:-is.: employed, as,- is preierred, relativelyfine strands areselectednsay,

.iorexample, thoserhavingaa diameter; ofs; about 40 0.006. A and: the .iabr-ic is preferably knitted:--to

: haverelativelysmall meshropeninggforexample,

. -.,about "1 5' -However,-. the-.- auge,- of the-strands -.-..and -.the size. of thesstitches may vary considerably; from athoseigiven abovegdependingnpon :the

45,;particular applicationsofthe product, the ,.charv-acter of. the, fillingtmaterial, and the like. oA-lso,

the strands maybe in. the. .form ofyronndewires ..-or flateut-strands; as desired.

rParticularly fonhighatemperatureapplications,

60 .the tubular body-M=has:asitsi-majortconstituent,

. a fibrous material SUChzfl-S asbestos fiber, although =.glass fibers, mineral wool fibers and. the. li-ke nay "be .used. For ..low .temperature .applioations,

,sfibrous materials. :of. either. an organic .or linor- :.ganic character-are. suitable-and:mayi-beiselected from the many known materials for similar uses, such as wood fibers, cotton fibers, and the like.

The arrangement of the fibers in the form of the tubular body I4 is maintained by a binder l6 distributed in minor proportions throughout the body, say in proportions of about 2 to 8'%. The selectionof the particular binders is not critical to the invention, binders of either a thermo-setting or thermo-plastic type being satisfactory, although thermo-setting resins are preferred. Examples are phenol-formaldehyde and accroides resins. Typical thermo-plastic binders which may be used are crude polystyrene resins, a natural resin such as batu gum in powdered form, pinewood pitch from which rosin and petroleum solvent soluble components have been extracted, and paracoumarone resins consisting of mixtures of polymerized coumarone and polymerized indene obtained from solvent-naphtha fractions of coal tar. Also, combinations of thermo-plastic and thermo-setting binders can be used in any desired proportions.

The tubular covering disclosed in Fig; 1 and described above may be readily applied to extending lengths of tubes, pipes and the like, by drawing or pushing the covering over the same, the readily stretchable, distortable character of the covering permitting it to conform to irregularities, changes in the dimensions, and the like.

Referring now particularly to Figs. 2-5 inelusive, the apparatus for the manufacture of the product described above and for carrying out the method of the instantinvention includes a device 20 for fabricating the tubular sleeve 52. Device 20 is preferably, as illustrated, a circular knitting machine of known type include a stationary cylinder 22 supporting a series of knitting needles 24. One or more spools 26 of the strand material from which the sleeve is to be fabricated are supported from the machine, as indicated at 28, to be rotated around cylinder 22, the strand extending from the supply through guide 30 to the knitting point; The drive for the knitting machine, supporting members and other conventional operating parts, such as the needle cam structure, and the like, have not been shown, and the knitting machine elements referred to above have been shown only diagrammatically as such features may be of any conventional or known type and, per se, form no part of the invention.

Supported above the knitting machine 20 as by bracket 32 is a delivery tube 34 having an upper section 36 and a lower, substantially cylindrical forming member 38 extending through the knitting machine cylinder and projecting some distance therebelow to terminate in an open mouth 40. Forming member 38 is of substantially the diameter of the knitted sleeve to be made on the machine 20. Upper section 36 is connected through a conduit or tube 42 to the out-put side of a blower or fan 44. A hopper I or the like 46 for the introduction of the fibrous material making up the insulating body i4 is in communication with the in-put side of the blower or fan. The latter is driven by any suitable means, such as motor 48. A metering de vice 50 of any known type may be employed to control the quantity of the fibrous material fed to the forming member through fan 44 and duct 42. The upper end of upper section 36 is closed by a cover 52. Extending axially of the delivery tube is a mandrel 54 including a head 56 partially within the forming member but projecting mandrel.

therefrom. The mandrel also includes a stem 58 extending upwardly through the cover 52 of upper section 36 and supported exteriorly of the delivery tube by bracket 56.

In the form of the invention shown in Figs. 2 and 3, mandrel head 58 and stem 58 are of hollow construction and the head isprovided with a plurality of perforations 62. Stem 5B is in communication exteriorly of the delivery tube with a suitable source (not shown) of heated fluid under pressure, such as heated, compressed air or steam, whereby the fluid may be led through the stem into head 56 and delivery through perforations 62.

Immediately below the mouth of forming member38 is a suction box 64 comprising a housing 66 surrounding the sleeve and tubular body, the housing being connected to a suction line 68 leading to a suction fan or the like (not shown) to obtain continuous withdrawal of air or other fluid from the body.

A chamber i8 is mounted below the suction box to surround the sleeve and tubular body. The chamber in the embodiment of Figs. 2 and 3 has outlet ports 12 and M, respectively, through which a heated fluid such as steam, hotair, or the like may be circulated from any suitable source of supply (not shown). The product comprising the knitted sheath and the tubular body is withdrawn downwardly through the several operating portions of the apparatus by suitable take-off means which may comprise, for example, pairs of opposed, concave, knurled rolls 76, driven in any suitable manner in timed relationship to the knitting operation.

In the operation of the apparatus described above and in carrying out the method of the instant invention, strand material of the kind selected for the sleeve [2 is supplied from spool 26 and is fabricated into a seamless, tubular fabric around forming member 38 by knitting machine 20. Coincident with this operation blower 44 is operated and the selected fibrous material, such as asbestos fiber, mineralwool fiber, glass fiber or the like, is supplied from the hopper 46 through measuring device 50 to the blower or fan and is carried with the airstream set up in conduit 42 into hopper section 36. The introduction of the fibrous material through the fan insures that it will be opened and fluffed and well dispersed before it reaches the delivery tube. The airstream, in addition to serving as a. conveyor for the fiber, serves as an impacting medium to pack the fiber between mandrel head 56 and the forming member to snugly fill the space therebetween. It will be understood that the density to which the fibers is packed will depend upon the quantity of fibers supplied and the force of the airstream, both of which are subject to control and may be varied to meet particular requirements.

The selected binder, a thermo-setting binder in the operation now being described, preferably in powdered form, is introduced with the fiber through hopper 46 and blower '44 and, due to the turbulence in the'airstream and the opening and fluffing of the fibrous material thereon; is distributed throughout the fibrous material.

Simultaneously with the operations described above, a heated fluid, suitably hot air or steam, at such a temperature that when mixed with the conveying air the temperature within the body will be sufiicient to liquefy and then .set. the thermo-setting binder, is supplied through the The heated fluid and the conveying ai eoaere fili -pass through the insulating' ibody up wi lftii-n the 'sleeve "and "ax-e exhausted through device fit. l I T As the *k'rlit'ted sleeve with -the tubular body therein passes downwardly fromthe a suction box 66,"- it is preferably subjected to an additional heat treatment-in chamber-1.0. A heated fluid, suitably-air or steam, at the r-equired 'temperatiire to set-the selected binder, is introduced into the chamber and circulate throughout, to insurethat the binder adjacent the exterior sur- 'fa'ceaot the body will be completely cured. No special" cooling steps are necessary though they r iay be em-ployed, "iff 'desired. the product leaves the take-off rolls it may becutiintotsec tions ofathe' desired .length and is then ready for use.

In the event'tha't itii's,:preferred;to concentrate .the bondedareas .of the. tubular -body adjacent the inner and outer peripheries to-leave. airla- .itwill effectively liquefy and cure only the binder adjacentt-he inner periphery of :the body. The

.binder adjacent the exteriorofthe body iscured solelybythe passage of the product throughthe ohamber-;'1-0.; H y p A similar result may be obtained byusing other means for the localized heating of the inner peripheral portion of the body. For example, as illustrated in Fig. 4, the mandrel may consist of a head 18 containing an electrical heating element 30, such as a conventional resistance heater, the electrical leads 82 for. the element extending through the stem 84 and being connected into a suitable source of current supply (not shown). The heat supplied by the mandrel primarily is applied directly to those portions of the body adjacent the inner periphery whereby the binder in such portions is cured and set, and the remainder is relatively unaffected. Suction device 66, in this instance, serves only to remove the conveying air and to prevent the emission of dust into the room. The heating of the body adjacent the outer periphery to cure the binder is accomplished entirely by the heating chamber 10.

The methods and apparatus described above may be used equally well where the binder is a combination of thermo-setting and thermoplastic materials with the thermo-setting ingredient in reasonable proportions, say in proportions of to 20% of the total binder. The thermo-setting material will be cured at the same time that the other binder ingredient is liquefied or softened and when used in such proportion will effectively maintain the shape of the body until the thermo-plastic material cools and hardens.

In cases where it is desired to employ a thermoe plastic alone or with a very small proportion of a thermo-setting material, the minor modifications of the apparatus illustrated in Fig. 5 are found desirable. In this case mandrel 86 has a head 88 including a perforate hollow section 90 lying partially within forming member 38, and partially projecting therefrom, and a solid, or at least imperforate section 92 extending from the perforate section through the suction device 66 and into a cooling chamber 94. The cooling chamber may be similar to heating chamber [0, except that its inlet and outlet ports 96 and 98, respectively, are in communication with a source of cold or refrigerated fluid.

. within-the body-beingcontrolled to soften the thermo-pl'astic bindersufiiciently to soften i-t, but preferably not to completely liquefy it, whereby it very quickly solidi-fies and exerts its binding function afterthe tubular body passes from "the heating zone. Inasmuch as the mandrel extends beyond the heating-zone, 'the'body-is maintained irrits required tubular shape until the binder "takes a sunicient set to preventcollapsingof the body. The solidification of the'biriderds-acceleratedasthetpro duct pass'e's through 5 the cooling zone-set up in chamber--94.

fIn "each of theseveral forms of the invention described above, "the tubular shape "of *the body ismaintained untilthe bind-er hasset'to'a sufiic'ient extentto'insureretention of the tubular "shape without "outside support. Thedensity of the body may be easily controlled by controlling the rate of deliveryof the'fibrous material and the velocity of the airstream "which carries the fibersinto the forming. member and servesasthe packing. medium. fj'Ihe.,bore-off the tubular body .may be; changed to meet particular, requirements by merely substituting mandrels.ofgthefdesired diameter. The product is of particular advantage for insulating lengths of tubing and the like which have numerous bends and turns as it may be easily forced onto the tubing from one end thereof, its flexible character permitting it to conform to the curvatures and other irregularlties in the line.

Having thus described my invention in rather full detail, it will be understood that these details need not be strictly adhered to but that various changes and modifications, may suggest themselves to one skilled in the art, all falling within the scope of the invention as defined by the subjoined claims.

What I claim is:

1. In the method of making a tubular covering, the steps comprising, fabricating a seamless, tubular sheath and substantially simultaneously therewith conveying a loose insulating material containing a thermo-plastic binder into the sheath and forming said loose insulating material into a tubular body within said sheath, heating the body to soften the binder and holding the tubular body against collapsing while cooling the binder.

2. The method defined by claim 1 in which the body is heated by the circulation of hot air therethrough.

3. In an apparatus for the manufacture of a flexible tubular covering, a hollow forming member having an open mouth, means for fabricating a tubular sleeve around the forming member, a hollow mandrel extending axially of said forming member, said hollow mandrel being in communication with a source of heated fluid and having openings for the emission of the heated fiuid therefrom, means for conveying a filling material containing a binder into said forming member to form a tubular body between said forming member and mandrel, and means for moving said sleeve forwardly as it is knitted to draw the sleeve from the forming member with the tubular body therein.

4, In an, apparatus as defined, by claim 3, means for applying heat to the exterior of said body.

5. In the method of making a tubular covering, the steps comprising, fabricating a seamless tubular sheath and simultaneously therewith conveying a loose insulating material containing a distributed unset thermo-setting binder into the sheath, forming said loose insulating material into a tubular body within said sheath, setting the binder by the circulation of a hot fluid through the tubular body, and holding the tubular body against collapsing during the binder-setting operation.

6. In an apparatus for the manufacture of a flexible tubular covering, a hollow forming member, means for fabricating a tubular sleeve around the forming member, a mandrel extending axially of said forming member, means for conveying a filling material containing a binder into the forming member to form a tubular body between the forming member and the mandrel, means for supplying a fluid medium to the body from the mandrel, suction means surroundingthe body to assist in the circulation of the fluid medium through the body, and means for moving the sleeve forwardly as it is fabricated to draw the sleeve from the forming member with the tubular body therein. 7. In an apparatus as defined by claim 3, suction means supported around the tubular body to assist the circulation of the heated fluid through the body.

8. Inan apparatus for the manufacture-of a flexible tubular covering, a hollow forming member having an open mouth, means for fabricating a tubular sleeve around the forming member. a mandrel extending axially of said forming memher, :said mandrel including a perforate hollow section andan imperforate. section, means connecting the hollow section with a source of a fluid medium, means for conveying 'a loose filling material containing a binder into said forming member to form a tubular body between said forming member and mandrel, and means for moving said sleeve forwardly as it is fabricated to draw the sleeve from the forming member with the tubular body therein. V

- EDWARD A. FARRELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

1. IN THE METHOD OF MAKING A TUBULAR CONVERING, THE STEPS COMPRISING, FABRICATING A SEAMLESS, TUBULAR SHEATH AND SUBSTANTIALLY SIMULTANEOUSLY THEREWITH CONVEYING A LOOSE INSULATING MATERIAL CONTAINING A THERMO-PLASTIC BINDER INTO THE SHEATH AND FORMING SAID LOOSE INSULATING MATERIAL INTO A TUBULAR BODY WITHIN SAID SHEATH, HEATING THE BODY TO SOFTEN THE BINDER AND HOLDING THE TUBULAR BODY AGAINST COLLAPSING WHILE COOLING THE BINDER. 